Spatial and temporal variations in the thermodynamics since the Last Glacial Maximum at Jutulstraumen drainage basin,East Antarctica

A flow-line model is coupled to a 2D temperature model to simulate the thermodynamic changes of Jutulstraumen drainage basin due to grounding line retreat and increased surface temperature since the Last Glacial Maximum (LGM). The basin consists of a plateau drained by an outlet glacier, and the simulated ice volume reductions are 1% and 2% respectively of the current grounded volume. The mountain ranges H.U. Sverdrupfjella and Neumayerskarvet fringing the plateau were not overridden by ice at the LGM, while the Nashornet nunataks closer to the grounding line were. Today the glacier is almost in balance with the current climate, with the highest thinning rate?<?5.0×10^?3 ma^?1 at the plateau. The simulated present-day thermal regime of the outlet glacier shows a basal layer at the pressure melting point and negative temperature gradients with depth due to horizontal advection of cold ice from the plateau. Sensitivity studies show that strain heating and horizontal advection are important for the basal temperatures in the fast flowing outlet glacier and for about half of the wide basin at the polar plateau. Increased strain heating and horizontal advection since the LGM control the response time required to readjust to the new conditions, and it controls the present-day volume.     

东北寨金矿床成矿机制：地球化学热力学研究

本文依据地球化学热力学方法圈定了东北寨微细浸染型金矿床的成矿条件，探讨了热液中金的溶解迁移形式及成矿过程。研究结果表明，Au（HS）-2和AuH3SiO04为金的主要迁移形式，随着主期硅化的发生，金的有效载体从AuH3SiO04转为Au（HS）-2；而AuCl-2的作用始终微不足道。石英及黄铁矿、辉锑矿等硫化物的沉淀是导致金成矿的主要因素。有机质对金成矿的贡献具有阶段性的意义。     

The Role of Initial Cloud Condensation Nuclei Concentration in Hail Using the WRF NSSL 2-moment Microphysics Scheme

The effects of the initial cloud condensation nuclei(CCN) concentrations(100–3000 mg~(-1)) on hail properties were investigated in an idealized non-severe hail storm experiment using the Weather Research and Forecasting(WRF) model, with the National Severe Storms Laboratory 2-moment microphysics scheme. The initial CCN concentration(CCNC) had obvious non-monotonic effects on the mixing ratio, number concentrations, and radius of hail, both in clouds and at the surface, with a CCNC threshold between 300 and 500 mg~(-1). An increasing CCNC is conducive(suppressive) to the amount of surface hail precipitation below(above) the CCNC threshold. The non-monotonic effects were due to both the thermodynamics and microphysics. Below the CCNC threshold, the mixing ratios of cloud droplets and ice crystals increased dramatically with the increasing CCNC, resulting in more latent heat released from condensation and frozen between 4 and 8 km and intensified updraft volume. The extent of the riming process, which is the primary process for hail production, increased dramatically. Above the CCNC threshold, the mixing ratio of cloud droplets and ice crystals increased continuously, but the maximum updraft volume was weakened because of reduced frozen latent heating at low level. The smaller ice crystals reduced the formation of hail and smaller clouds, with decreased rain water reducing riming efficiency so that graupel and hail also decreased with increasing CCNC, which is unfavorable for hail growth.     

岩浆硫化物矿床研究现状及重要科学问题

20世纪90年代,岩浆通道成矿模型的提出为岩浆硫化物矿床成因研究提供了崭新的思路,但对成矿机制和找矿标志的认识依然存在分歧。2000年以来,不同学者从岩浆通道形成的构造因素,外来硫加入的方式和控制因素,硫化物熔离、运移和沉降的热力学条件及动力学机制,区域找矿标志等方面对岩浆通道成矿机理进行了更深入的探讨。最近的研究发现,原来建立在热力学平衡假设基础上的一些认识需要纠正,硫化物熔离的化学动力学机制以及岩浆流体动力学状态对矿床的地质和地球化学特征具有不可忽视的影响,玄武岩铂族元素亏损的形成机制和找矿意义需要重新认识。     

The truth and beauty of chemical potentials

This essay in honour of Mike Brown addresses aspects of chemical equilibrium and equilibration in rocks, with a focus on the role that chemical potentials play. Chemical equilibrium is achieved by diffusive flattening of chemical potential gradients. The idea of equilibration volume is developed, and the way equilibration volumes may evolve along a pressure–temperature path is discussed. The effect of the environment of an equilibration volume is key to understanding the evolution of the equilibration volume with changing conditions. The likely behaviour of equilibration volumes is used to suggest why preservation of equilibrium mineral assemblages and mineral compositions from metamorphism tends to occur. This line of logic then provides the conceptual support to conventional equilibrium thermodynamic approaches to studying rocks, using, for example, thermobarometry and pseudosections.     

高岭石,铝土矿共生及相变的热力学讨论

根据热力学计算,在常温常压下,铝土矿物能与石英自发反应生成高岭石;硬水铝石和三水铝石都能自发转变为勃姆石,三者可以共生;硬水铝石会自发相变为勃姆石,可能为原生的;在沉积和成岩期的环境下,SiO_2和铝土矿均能化合生成高岭石。     

溶解性石油烃在砂上的吸附和解吸研究

采用海滨浴场的沙为吸附剂,0号柴油为吸附质,研究了溶解性石油烃（DPHs）在砂上的吸附及解吸规律.研究发现,砂对DPHs的吸附和解吸均符合一级反应模式;油的解吸速率比吸附速率慢13倍,并且有约25%的油残存于砂上, 因而污染威胁会在较长时间内存在.砂对海水中DPHs的吸附等温线可以用Henry型等温式描述,温度越高,海水中的油向砂上转移的量越小.通过吸附热力学分析,得出该吸附属于物理吸附范畴.     

哈密地区南部一次大降水机制分析

对造成哈密南部"2000·6·23"大降水的主要影响系统南疆低槽、北方冷空气、中低层切变等进行了描述,并从热力因素、动力因素两方面对其特征予以剖析,得到哈密南部大降水预报的某些着眼点.     

北极多冰年和少冰年的大气环流差异

本文利用一个改进的海冰热力模式,取北极区大气和有关场的气候资料,模拟了1982年10月至1988年9月的北极海冰空间分布和季节变化的循环特征,较好地模拟出多冰年（1983,1987）和少冰年（1984,1986）。模拟结果与部分研究工作以及实况相比较,基本状况趋于一致。并且在此基础上进一步探讨了北极多冰年和少冰年的大气环境差异,可以看到多冰年的北极极涡偏西半球;少冰年的北极极涡基本是围绕极地。从而进一步影响多冰年和少冰年大气环流差异,特别是对亚洲环流的影响较大。     

A new technique of physical dissipation and its application to a mesoscale numerical weather prediction model

In terms of statistical physics, a fluid such as the atmosphere is a many-body system which has a vast amount of degree of freedom and thus obeys the second law of thermodynamics. In this paper, a noticeable improvement of the prognostic outputs is made by reconstructing the terms of the horizontal diffusion of MM5 according to the principles of the second law of thermodynamics; besides, the computational noise is effectively and significantly suppressed since the physical dissipative technique for reconstructing suggested in this paper is based on the physical law rather than on the computational method such as the artificial viscosity.